In an optical disk recording and reproducing drive which records/reproduces information of optical disks such as a CD (Compact Disk), a DVD (Digital Versatile Disk), a BD (Blu-Ray Disk), etc., laser light emitted from an optical pickup is applied onto an optical disk recording surface and its reflected light is detected by the optical pickup, so that an RF analog reproduction signal is generated. The recording and reproduction of such an optical disk recording and reproducing drive needs various control such as spindle drive, tracking control, focus control, etc. For various control, the RF analog detection signal detected by the optical pickup is converted to a digital signal by an A/D converter of a semiconductor integrated circuit, which in turn is subjected to digital signal processing inside the semiconductor integrated circuit.
A patent document 1 has described that measured data read from digital signal recording mediums such as a CD and a DVD are sequentially stored in a memory, and the data stored in the memory are outputted via an interface to a host device by which the result of measurement is displayed. This technology enables no need for a conventional expensive dedicated measuring device.
A patent document 2 has described that in order to measure various signals inside a servo controller without dismounting a disk recording and reproducing drive in the disk recording and reproducing drive, a monitor controller determines which internal signal in the servo controller should be output by a detection device. In a test mode, the internal signal of the servo controller outputted from the monitor controller is outputted to its corresponding external detection device via a selector, an audio output D/A converter and an audio output terminal.